“You thought I was a mere toy! Well, now it's time I toy with *you*!”
—Master Computer

Master Computer is the eponymous character from the video game of the same name.

Early on in the episode, Game Over, Dexter stated that he previously owned and mastered the game when he was three, then quickly discarded it. Years later, Dexter's Dad bought the game from a gypsy for a nickel (he clearly only bought it for the "bargain" price). After Dexter got it, he immediately discarded the game.

However, Dee Dee found the game and challenged Dexter to a Master Computer showdown, with Dexter easily defeated. Afterwards, he tried to remove the game but failed, as Master Computer then revealed himself, stating that he wanted revenge for his abandonment. He then started infecting the circuitry of Dexter's Computer, only leaving a small amount of core system memory.

He then digitized Dexter and began to torture him. However, Dexter used the last bit of Core Energy to contact Dee Dee so he could escape. Dee Dee beat Master Computer then halting its program. The game cartridge was quickly removed, and Master Computer has not appeared since.

Features

Dexter's disregard about this game is mainly because it is an old game, and its features are, as stated in the Game Over episode:

Vertex graphics

8 bit memory

1 level of play

No scaling capabilities

No digital stereo sound

No multi-player

No secret codes

No bleeding players or bosses

Dexter stated that there was no multi-player support. However, he battled Dee Dee in a multi-player game. This could have been an upgrade due to the game being played on Dexter's supercomputer instead of the average game console.

This could have been the same assumed upgrade that awakened the Master Computer program.

Dexter may have lied about the game not having multi-player, for he assumed he would be beaten easily by Dee Dee.

Trivia

Master Computer is a parody of the MCP (Master Control Program) from Disney's 1982 film, Tron.